By CATHERINE MILLER
Sheep producers are being urged to be on high alert for blowfly strikes in their flocks, with warm, humid weather creating ideal conditions.
Both Elanco and Coopers Animal Health have reported a jump in sales of preventative products offering three months protection or more against flies.
Pro Ag Consulting livestock consultant Colin Trengove said the conditions in the past few weeks had increased the risk across much of the state.
Shearing and crutching sheep and lambs offered the best protection, along with a preventative chemical off-shears.
“Most producers who have not sold their woolly lambs by December are shearing now anyway so their risk is minimised for at least six weeks and we have seen plenty of people who used (preventative) products in the spring that last three to six months,” Dr Trengove said.
“With the (high) price of any age of sheep compared to the chemical cost, why would anyone take the risk, especially those busy with other activities on farm like harvest?”
“Never assume it is 100 per cent effective though, with hand jetting or spraying there can always be human error.”
In deciding which product to treat their flocks with, Dr Trengove said producers needed to consider the meat and wool withholding periods and export slaughter intervals, with some up to six months.
He said there were a limited number of insecticides on the market to treat struck sheep but encouraged producers to look at the Australian Wool Innovation and Meat & Livestock Australia-funded FlyBoss website for their full range of options.
Dr Trengove said it was also pleasing many sheep breeders were reducing their susceptibility to flystrike through breeding animals with low dag and wrinkle scores and focusing on fleece colour.
Coopers’ SE of SA territory sales manager Pene Keynes said weather conditions were conducive to a severe blowfly season.
“Sales of blowfly preventative chemicals like Coopers Blow Fly and Lice have significantly increased as producers look to protect their flock,” she said.
Elanco sheep brand manager Kathryn Humphries said there had been strong interest in CLiK Extra, a new formulation released this year that can provide up to 29 weeks’ protection against flystrike.
This is up to five weeks longer than its CLiK product that has been available for about 20 years.
New index warns of high-risk weather
A NEW index is being developed to help producers predict the risk of flystrike in their flocks.
The Barossa Improved Grazing Group is using the data collected at its three weather stations – at Koonunga, Flaxman Valley and Keyneton – and working with Moonta-based technology expert Peter Toome on a model to warn about high-risk periods.
BIGG technical facilitator Brett Nietschke says the sheep blowfly index is about being proactive in managing a scourge of the sheep industry.
“Producers know when it is rainy and hot the chance of flystrike really increases but it really needs three things to line up – temperature, wind and rainfall,” he said.
Industry research has shown that for the greatest chance of flystrike, three days of at least five millimetres of rain are needed.
At the same time, wind speeds need to be between nine metres a second and 30m/sec and temperatures between 25 degrees Celsius and 38C.
“The Flaxman Valley site has reached the watch rating three times in the past month, while at the Koonunga site the rating has been high twice in the past two weeks” he said.
Mr Nietschke says the index is a chance to “value-add” to the local data generated at BIGG’s weather stations, similar to frost and fire harvest indexes already developed.
“Rather than using the climate data default which could be 20km, 30km or 40km away from your property, we are looking at more accurate localised data,” he said.